Zhaoyang Zhang Peng Cheng Xiangwei Zhou Peiliang Qiu System synchronization and channel estimation analysis for IEEE 802.16e OFDMA downlink system. 375-398 2009 22 Int. J. Communication Systems 4 http://dx.doi.org/10.1002/dac.965 db/journals/ijcomsys/ijcomsys22.html#ZhangCZQ09